Sioux Falls

The pilot was conducting a cross-country flight when, about 8 miles north of his intended destination, he reduced engine power, pitched for level flight, and waited for indicated airspeed to drop below 174 kts to add 20° of flaps. As soon as the drag was introduced, the airplane began to “buck back and forward,” and the two engines were “throttling up and down on their own.” He noted that the right engine seemed to be “sputtering and popping” more than the left engine, so he decided to raise the flaps and to shut down and feather the right engine. He declared an emergency to air traffic control. The pilot then noticed that the left engine was “slowly spooling down” and the airplane was not able to maintain airspeed and altitude. The pilot performed a forced landing to a flat, muddy wheat field about 4 nautical miles from the airport. The airplane sustained substantial damage to the fuselage and to both wings. A Federal Aviation Administration inspector traveled to the accident site to examine the airplane. Flight control and engine control continuity were confirmed. The master switch was turned on and the fuel gauges showed a zero indication. There was no evidence of fuel at the accident site or in the airplane. During the recovery of the airplane from the field, no fuel was found in the three intact fuel tanks, nor in any of the engine fuel lines. The pilot later stated that he ran the airplane out of fuel during the accident flight. The pilot reported that, during the preflight checks and twice during the accident flight, he activated the low fuel warning light, and no anomalies were noted. Postaccident testing of the low fuel warning light in an exemplar Piper Aerostar 602P revealed no anomalies.

The pilot departed on a cross country flight in a turbine-powered, multiengine airplane at night and in visual meteorological conditions. Recovered GPS data revealed that as the airplane accelerated down the runway, it drifted to the right of the runway centerline. A video recording showed that shortly after takeoff, the airplane rolled right, the nose dropped, and the airplane impacted the ground. It came to rest on its left side with both wings separated and the fuselage was highly fragmented forward of the main landing gear. A post-accident examination of the airframe and engines found no mechanical malfunctions or anomalies that would have precluded normal operation. A witness that spoke to the pilot shortly before the accident flight stated that the pilot exhibited difficulty in completing some paperwork; however, no medical reasoning for this difficulty could be determined based upon the available evidence. The investigation determined that at the time of the accident the pilot had been on duty for about 19 hours and 20 minutes, which was contrary to duty and rest regulations. At his estimated arrival time into the destination, the pilot would have accumulated about 20 hours and 54 minutes of duty time. The investigation was unable to determine if the pilot took advantage of the opportunity for rest that existed during the day, and therefore could not determine if fatigue contributed to the accident. Investigators were unable to determine the reason for the loss of control on takeoff with the available information.

Shortly after the airplane lifted off, the tower controller informed the pilot that a plume of smoke was visible behind the airplane. No communications were received from the pilot after he acknowledged the takeoff clearance. Witnesses reported that white smoke appeared to be trailing from the area of the left engine during takeoff. The witnesses subsequently observed flames at the inboard side of the left engine. The airplane began a left turn. As the airplane continued the turn, the flames and trail of white smoke were no longer visible. When the airplane reached a southerly heading, the nose dropped abruptly, and the airplane descended to the ground. Witnesses stated that they heard an increase in engine sound before impact. A postimpact fire ensued. The accident site was located about 3/4 mile from the airport. A postaccident examination determined that the left engine fuel selector and fuel valve were in the OFF position, consistent with the pilot shutting down that engine after takeoff. However, the left engine propeller was not feathered. Extensive damage to the right engine propeller assembly was consistent with that engine producing power at the time of impact. The landing gear and wing flaps were extended at the time of impact. Teardown examinations of both engines did not reveal any anomalies consistent with a loss of engine power. The left engine oil cap was observed to be unsecured at the accident site; however, postaccident comparison of the left and right engine oil caps revealed disproportionate distortion of the left oil cap, likely due to the postimpact fire. As a result, no determination was made regarding the security of left engine oil cap before the accident. Emergency procedures outlined in the pilot’s operating handbook (POH) noted that when securing an engine, the propeller should be feathered. Performance data provided in the POH for single-engine operations were predicated on the propeller of the inoperative engine being feathered, and the wing flaps and landing gear retracted. Thus, the pilot did not follow the emergency procedures outlined in the POH for single-engine operation.

The single-engine airplane experienced a loss of engine power during cruise flight at flight level 190 (19,000 feet) and impacted the terrain while performing a forced landing to a nearby airport. Visual meteorological conditions prevailed at the time of the accident with clear skies and unrestricted visibilities. The pilot reported the loss of engine power about 16 minutes prior to the accident and requested clearance to the nearest airport. Air traffic control (ATC) issued vectors to the Southwest Michigan Regional Airport (BEH). About 10 minutes prior to the accident, the airplane was positioned approximately 1.3 nm north of BEH at 13,500 feet. The pilot elected to follow ATC vectors verses circling down over BEH. ATC provided vectors for runway 27 at BEH. Witnesses to the accident reported seeing the airplane "spiraling down and crashing into the ground." The wreckage was located on the extended runway 27 centerline, about 1.12 nm from the runway threshold. The distribution of the wreckage was consistent with a stall/spin accident. Approximately four minutes before the accident, the airplane was on a 9.5 nm final approach at 6,700 feet. Between 9.5 and 5.3 nm the airspeed fluctuated between 119 and 155 knots, and the descent rate varied between 1,550 and 2,600 feet/min. Between 5.3 nm and the last radar return at 1.5 nm the airspeed dropped from 155 to 78 knots. According to the Pilot Operating Handbook (POH) the accident airplane should be flown at best glide speed (92 knots) after a loss of engine power. An average engine-out descent rate of 700 feet/min is achieved when best glide speed is maintained during engine-out descents. An engine teardown inspection revealed that the crankshaft was fractured at the number five crankpin journal. Visual examination of the crankshaft (p/n 13F27738, s/n V537920968) showed a fatigue-type fracture through the cheek, aft of the number five crankpin journal. The exact cause of the crankshaft failure could not be determined, due to mechanical damage at the fatigue initiation point. The fracture features for the accident crankshaft was consistent with 14 previous failures of the same part number. The engine manufacturer determined the failures were most likely due to the overheating of the steel during the forging process.

The airplane was cruising at 6,000 feet where it encountered icing conditions. When cleared to 3,600 feet, the pilot reported that one engine lost all power and the other one was running rough. The airplane continued the descent. After about ten minutes the airplane departed controlled flight, reversing heading and impacting near vertically in the terrain. A post accident examination of the left engine (which was feathered) found an induction duct which had deteriorated and begun to come apart. Foreign object material in the compressor assembly similar in appearance to material from the duct was found. The number five piston had a hole burned through it.

Witnesses observed the aircraft for approximately 8 minutes in erratic diving, climbing, and steep-turning maneuvers which culminated in a 12° descent to the ground. The sound of the engine was heard throughout the sequence and other evidence indicated engine power at impact. The aircraft struck trees, a farm building, farm equipment, and a vehicle, then burst into flames. The wreckage was strewn along a 320 feet path. No evidence of flight control malfunction was found. The pilot claimed an upset stomach before the flight. The pilot's speech was slurred in radio transmissions. The pilot did not respond to the last radio call from Sioux Falls tower. No emergency or distress calls were received from the pilot. The postmortem examination of the pilot did not identify specific impairment but was limited due to the severity of the impact and fire damage.